Top risk factors for skin cancer

Q: "I love being out in the sun, but I have light skin that tends to burn and freckle. Should I be worried about skin cancer? What are the main risk factors? How can I reduce my risks?"

Answered by Brendan Curti, M.D., medical oncologist, director of the Providence Biotherapy Program at Providence Cancer Center and director of genitourinary oncology research at the Robert W. Franz Cancer Research Center in the Earle A. Chiles Research Institute.

We all should be concerned about skin cancer. It's the most common form of cancer in the United States, affecting about one in five Americans in their lifetime. Anyone can get it, but your risk is higher than average if you spend a lot of time in the sun – especially if your skin burns and freckles. Here in the Pacific Northwest, skin cancer rates are high and have increased in the last decade.

The leading risk factor for skin cancer is exposure to ultraviolet, or UV, radiation. That includes the UV that you absorb from the sun, as well as from tanning beds. As wonderful as those warm rays may feel on your skin, UV radiation has been identified by the World Health Organization as a proven carcinogen.

How bad is UV exposure, really? According to

  • The International Agency for Research on Cancer lists UV radiation from the sun and from indoor tanning devices among the "Group 1" carcinogens – the most dangerous of all cancer-causing agents.
  • Just one sunburn can increase your lifetime risk of melanoma, the deadliest form of skin cancer. After five sunburns – or one blistering sunburn in childhood or adolescence – the risk of melanoma doubles.
  • People who use UV tanning facilities or devices are 74 percent more likely to develop melanoma than people who don't use them.
  • In May of 2014, the FDA reclassified the UV lamps used in sunlamp tanning products as devices that carry moderate risk (previously they were classified as low-risk). Furthermore, there will be a "black box" warning on all sunlamps stating that they should not be used by anyone under the age of 18.

UV exposure, tanning and burning are all things that you can control with a few simple precautions. But there are other risk factors that you can't control (although my 16-year-old would argue about whether or not she can control her hair color). These include:

  • Light skin, hair or eye color
  • Freckles
  • Numerous moles on your skin
  • Family or personal history of melanoma

If you have any of these known skin cancer risk factors, or if you've had sunburns in the past or a lot of sun exposure early in your life, then it's especially important to be sun smart now. Everyone – and especially people at high risk – should practice these precautions:

Be on the lookout for skin changes: Take a close look at your skin – all of it, head to toe – every month. If you notice any changes in a freckle or mole, have your doctor or dermatologist take a look. Don't rely on mole-mapping apps to try to diagnose yourself – they can't substitute for an examination by your doctor.

See a dermatologist every year: Everyone at high risk for skin cancer should get a full-body skin exam from a dermatologist once a year, even if everything seems to look OK. There's no substitute for an expert's opinion.

Slather on the sunscreen: Choose an SPF 30 or greater. Put it on at least 30 minutes before you go outside, and reapply often. Use it every day, whether it's warm or cool, sunny or cloudy. Any questions? See these excellent sunscreen FAQs.

Cover up: Protect your head and neck with a broad-brimmed hat. Protect your eyes with a good pair of UV-blocking sunglasses. Protect the rest of your body with UV-blocking clothes – you can find them at most outdoor-clothing stores.

Head for the shade: The best way to prevent skin cancer is to avoid the sun when it's at its strongest, between 10 a.m. and 2 p.m. at a minimum, and ideally until 4 p.m. As for tanning salons: Avoid them 24/7, 365 days a year.

Don't assume that darker skin protects you: You can get skin cancer no matter what your skin type. In fact, one of the deadliest forms of melanoma is more common in people with darker skin. Take this skin quiz for specific recommendations for your skin type.

I'm not suggesting that you need to live in a cave to stay safe, even if you do have risk factors. But do respect the power of the sun and the impact that UV has on your skin. 


Dr. Curti and Walter Urba, M.D., Ph.D., coauthored the chapter on Cancers of the Skin in the 2014 edition of the medical textbook Harrison's Principles of Internal Medicine, to be published soon. Dr. Urba is the director of cancer research at Providence Cancer Center.